Gastrin-releasing peptide

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Gastrin-releasing peptide
Identifiers
Symbols GRP ; BN; GRP-10; preproGRP; proGRP
External IDs OMIM137260 MGI95833 HomoloGene1580 GeneCards: GRP Gene
RNA expression pattern
PBB GE GRP 206326 at tn.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 2922 225642
Ensembl ENSG00000134443 ENSMUSG00000024517
UniProt P07492 Q8R1I2
RefSeq (mRNA) NM_001012512 NM_175012
RefSeq (protein) NP_001012530 NP_778177
Location (UCSC) Chr 18:
56.89 – 56.9 Mb
Chr 18:
65.87 – 65.89 Mb
PubMed search [1] [2]

Gastrin-releasing peptide, also known as GRP, is a neuropeptide, a regulatory molecule that has been implicated in a number of physiological and pathophysiological processes. Most notably, GRP stimulates the release of Gastrin from the G cells of the stomach.

The gene from which GRP is derived encodes a number of bombesin-like peptides.[1][2][3][4] Its 148-amino acid preproprotein, following cleavage of a signal peptide, is further processed to produce either the 27-amino acid gastrin-releasing peptide or the 10-amino acid neuromedin C. These smaller peptides regulate numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation.[1]

Function[edit]

Gastrin-releasing peptide is a regulatory human peptide that elicits gastrin release and regulates gastric acid secretion and enteric motor function.[5] The post-ganglionic fibers of the vagus nerve that innervate the G cells of the stomach release GRP, which stimulates the G cells to release gastrin.

GRP is also involved in the biology of the circadian system, playing a role in the signaling of light to the master circadian oscillator in the suprachiasmatic nuclei of the hypothalamus.

Furthermore, GRP seems to mediate certain aspects of stress. This is the reason for the observed fact that atropine does not block the vagal effect on gastrin release.

Gene[edit]

The human GRP gene is located on chromosome 18. PreproGRP (the unprocessed form of GRP) is encoded in three exons separated by two introns.[4] Alternative splicing results in multiple transcript variants encoding different isoforms.[1]

Synthesis[edit]

PreproGRP begins with signal peptidase cleavage to generate the proGRP, which is then processed (by proteolytic cleavages), to form smaller GRP peptides.[5]

These smaller peptides are released by the post-ganglionic fibers of the vagus nerve, which innervate the G cells of the stomach and stimulate them to release gastrin. GRP regulates numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation.[5]

Clinical significance[edit]

Gastrin-releasing peptide and neuromedin C, it is postulated, play a role in human cancers of the lung, colon, stomach, pancreas, breast, and prostate.[1]

References[edit]

  1. ^ a b c d "Entrez Gene: GRP gastrin-releasing peptide". 
  2. ^ Spindel ER, Chin WW, Price J, Rees LH, Besser GM, Habener JF (September 1984). "Cloning and characterization of cDNAs encoding human gastrin-releasing peptide". Proc. Natl. Acad. Sci. U.S.A. 81 (18): 5699–703. doi:10.1073/pnas.81.18.5699. PMC 391778. PMID 6207529. 
  3. ^ Spindel ER, Zilberberg MD, Habener JF, Chin WW (January 1986). "Two prohormones for gastrin-releasing peptide are encoded by two mRNAs differing by 19 nucleotides". Proc. Natl. Acad. Sci. U.S.A. 83 (1): 19–23. doi:10.1073/pnas.83.1.19. PMC 322782. PMID 3001723. 
  4. ^ a b Lebacq-Verheyden AM, Bertness V, Kirsch I, Hollis GF, McBride OW, Battey J (January 1987). "Human gastrin-releasing peptide gene maps to chromosome band 18q21". Somat. Cell Mol. Genet. 13 (1): 81–6. doi:10.1007/BF02422302. PMID 3027901. 
  5. ^ a b c Merali Z, McIntosh J, Anisman H (October 1999). "Role of bombesin-related peptides in the control of food intake". Neuropeptides 33 (5): 376–86. doi:10.1054/npep.1999.0054. PMID 10657515. 

Further reading[edit]

External links[edit]